I have used BookBub once before for my first novel, Watch Me Disappear, and it was my most successful promotion. That time I discounted the book to $0.99. In fact, I was quite happy to have enough downloads during that promo to fully pay for the rather steep cost of the BookBub promo and even have a little cash leftover.
For What She Inherits, I took the plunge and paid the big bucks--$433.00--to tell the world I was giving my eBook away for free for one week. One week later, it feels like money well spent.
